Metaphysical Themes 1274–1671. : Oxford University Press, 2011-02-01. Oxford Scholarship Online. 2011-05-01. Date Accessed 24 May. 2013 <http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199567911.001.0001/acprof-9780199567911>.
(2011-02-01). Metaphysical Themes 1274–1671. : Oxford University Press. Retrieved 24 May. 2013, from http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199567911.001.0001/acprof-9780199567911.
Metaphysical Themes 1274–1671. : Oxford University Press, 2011-02-01. http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199567911.001.0001/acprof-9780199567911.
Pasnau R. Metaphysical Themes 1274–1671. Oxford University Press; 2011. http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199567911.001.0001/acprof-9780199567911. Accessed May 24, 2013.